Abstract
Objective. To assess if pressure-support ventilation (PSV) can improve ventilation-perfusion (VA/Q) imbalance observed during the transition from positive-pressure ventilation to spontaneous breathing in intubated chronic obstructive pulmonary disease (COPD) patients during weaning.
Design. Prospective study.
Setting. Respiratory intensive care unit of a tertiary university hospital.
Patients. Seven mechanically ventilated COPD male patients (age 68±6 (SD) years; FEV1 26±6% predicted) during weaning.
Interventions. Patients were studied during three ventilatory modalities: (1) assist-control ventilation (ACV), tidal volume (VT), 8–10 ml . kg–1; (2) PSV aimed to match VT in ACV, 15±1 cmH2O and (3) spontaneous breathing.
Measurements and results. Arterial and mixed venous respiratory blood gases, VA/Q distributions, hemodynamics and breathing pattern were measured. Compared with both ACV and PSV, during spontaneous breathing patients exhibited decreases in VT (of 43%, p<0.001) and increases in respiratory rate (of 79%, p<0.001), PaCO2 (of 8.5 mmHg, p=0.001), cardiac output (of 27%, p<0.001) and mixed venous oxygen tension (of 3.4 mmHg, p=0.003), while PaO2 remained unchanged throughout the study. Except for a shift of the pulmonary blood flow distribution to areas with lower VA/Q ratios (p=0.044) and an increase of dead space (of 25%, p=0.004) during spontaneous breathing, no other changes in VA/Q distributions occurred. No differences were shown between ACV and PSV modalities.
Conclusion. In COPD patients during weaning, PSV avoided VA/Q worsening during the transition from positive-pressure ventilation to spontaneous breathing. Hemodynamics, blood gases or VA/Q mismatch were no different between ACV and PSV when both modalities provided similar levels of ventilatory assistance.
Article PDF
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Electronic Publication
Rights and permissions
About this article
Cite this article
Ferrer, M., Iglesia, R., Roca, J. et al. Pulmonary gas exchange response to weaning with pressure-support ventilation in exacerbated chronic obstructive pulmonary disease patients. Intensive Care Med 28, 1595–1599 (2002). https://doi.org/10.1007/s00134-002-1490-4
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s00134-002-1490-4